Archive for the ‘Stories from the Field’ Category

Rethinking ‘Cash for Clunkers’

August 11th, 2009 2 comments

C.A.R.SThere is no doubt that the Car Allowance Rebate System, or “Cash for Clunkers” program has proved to be popular with American car buyers.  So popular in fact, that it ran out of cash within the first six days of processing claims.  This news got me thinking about the program in a more systemic way.

Whether you think of the program as a stimulus for the economy or the environment, it cannot continue to operate without funds.  Congress had to quickly approve another $2 billion for the program when the initial $1 billion appropriation was exhausted in less than a week.  The rebate fund lacks an inflow of cash to offset the outflow of payments.

I wrote about a STELLA model of a self-financing program to promote cleaner vehicle sales in May.  The “Feebates” model uses fees charged on sales of vehicles that have high pollution rates to finance rebates for cleaner vehicles.  I asked the Feebates model author, Andrew Ford what he thought about “Cash for Clunkers”.  He sent me an article he co-authored with Todd BenDor titled “Simulating a combination of feebates and scrappage incentives to reduce automobile emissions”.  Basically, the article describes a feebates model with a “cash for clunkers” type of rebate added to promote scrapping older vehicles.  The article was published in the journal Energy, 31(2006), 1197-1214.

3808715790_393164d861Mr. BenDor was kind enough to send me the STELLA model so we could publish it to the web with isee Netsim.  We thought this would be a great way to start some discussion around the Clunkers program, public policy and using simulations to facilitate decision making.

Click here to run the simulation online.

  • Can you design a policy that stimulates the economy and reduces emissions?
  • This simulation uses fees to fund the program instead of deficit spending.  What other sources of revenue could we consider?
  • Many states levy a “sin tax” on tobacco and alcohol.  How would the public react to fees on high-pollution vehicles?

Post your answers in the comment section below.

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Building a Health Care Model Hierarchically

June 10th, 2009 2 comments

I recently had the pleasure of building a very large model of the health care system from many small discrete parts.  I did this in a course on Health Care Dynamics taught by James Thompson at Worcester Polytechnic Institute.  The design of the model is entirely Jim’s.

The most striking thing about this model to me is that it was created completely hierarchically.  I have seen many large models broken into sectors which are conceptually all at the same level.  I have seen other large models that are organized by feedback loops, which can at some times be large and unwieldy.  But I had yet to see an example that is truly hierarchical, with an appropriate dynamic hypothesis at each level.

The model is three-levels deep.  At the lowest level are models with very simple dynamic hypotheses.  At the next level up, groups of these smaller models are tied together to form more complex feedback loops, or loop sets, comprising a higher-level dynamic hypothesis (this is the complexity most of the models I develop have).  At the top-level, they are tied together to form a very high-level dynamic hypothesis.  One of the very nice things about this is that each part of the model, which was built bottom-up, has already been tested in isolation or within its group before the whole model is tied together.  All parts are in steady-state.  In this way, we have built confidence in all of the parts of the model and now are only testing the broadest feedbacks.


Critics of this approach insist that delaying the connection of the broadest feedbacks until this late in the development of the model hides important dynamics that affect all parts.  Not only is this considered risky, but the model does not generate results until the end.  After this experience, I can’t agree with this point-of-view.  There was very little risk in tying the pieces together at the end because they were well-formed pieces already rich in feedback, and (very important!) initialized in steady-state.  While the model did not address some of the overarching issues until the end, careful testing of the pieces of the model added insight at many steps along the way and even gave hints about what might happen when those final feedbacks were put into place.

Read more…

Published Papers that Feature Models

April 6th, 2009 5 comments

sd-review-006One of our customers suggested we compile a list of articles after being asked to submit a paper about his STELLA model. We thought a list of published papers about STELLA and iThink models was a great idea. The information would not only be useful to people writing papers, it would be a wonderful resource for folks wanting to learn about other modeling projects.

It occurred to us that the blog would make a good home for the list because others could help keep it current by posting comments with links to newly published papers or papers we may have missed.

To get the ball rolling, we compiled a list from journals we are familiar with – System Dynamics Review and Journal of the Operational Research Society. The result is by no means exhaustive. It is simply a way to get things started. We need your help to expand this list and to include other journals that you’re reading.

If you know of a published paper about a STELLA or iThink application that does not appear on this list, please let us know about it by submitting a comment. It would be helpful if you included citation information so that we can quickly verify it and update our list.

Thanks for your help!

Click here to see the list

Medici’s Lever – An Online Cultural Policy Game

April 2nd, 2009 No comments
Medici's Lever consists of educational games and a freestyle laboratory that enables users to set game parameters

Medici's Lever consists of educational games and a freestyle policy laboratory

A couple of months ago, Steve Peterson came by the office and showed me an online game created with iThink and isee NetSim called Medici’s Lever.  I was really impressed.

The game begins in San Jose, California.  Dr. Lilia Maria Delgado, a legend of Silicon Valley’s rise to high-tech super power, has died and left a half-billion dollars to establish the “Delgado Arts Endowment”.  In her will, Dr. Delgado simply states that the mission of the Endowment is to advance the cultural life of San Jose.

Your job is to fulfill the mission by experimenting with the various approaches of five different CEO candidates over a 40 year period.  Each candidate personifies a different theory of arts and cultural development and provides you with different investment levers that impact overall “cultural vitality”.

The San Jose Rennaissance is one of two educational games that are a part of Medici’s Lever.  The other game is very similar but takes place in a different region — this time a fictitious European city dubbed the Capital of Culture.

The final module of Medici’s Lever is an interactive Policy Laboratory that lets the user “dial in” initial parameters to define the region in which they want to experiment.

The 3 elements of the "logic model" are displayed as a pyramid in the games

The 3 elements of the "logic model" are displayed as a pyramid in the games

Medici’s Lever is powered by an underlying iThink model (although users are unaware of this).  The games inform the player that it is driven by a “logic model” they must keep in mind when experimenting.

The premise of the logic model is: In order to maintain a healthy cultural ecology a region must strike a balance between three elements — cultural literacy, participation in cultural expression, and consumption of professional cultural goods and services.

In the games, the three elements are visualized as a pyramid.  What I found out after a couple of runs is that investing in the bottom of the pyramid pays off in the long-term.  The insight I gained was that a community needs to have people who appreciate art and culture and actively participate in it from a young age to be successful supporting the professional artists. In other words, it does not make sense to invest in a state-of-the-art performance hall if no one wants to attend the performances.

I think Medici’s Lever is an excellent example of how you can get folks thinking about a systemic issue in an easy and engaging way.

Background and Development

Medici’s Lever is the final project of Cultural Initiatives Silicon Valley, an organization that worked to implement a ten-year cultural plan for Silicon Valley from 1996 to 2006.  John Kreidler, Cultural Initiatives’ retired Executive Director, is responsible for the model concept and design.  The iThink model and web interfaces were developed by Steve and published online with isee NetSim.


It is important to note that at its inception, Cultural Initiatives planned to operate for one decade only.  As the end of that decade approached, John and Steve began working on bringing all of the ideas of the foundation together in a model that could be played as a game.  It was key that the game live online so others could benefit from the insights of the foundation long after it had sunset.

When Steve started developing the iThink model for the game, isee NetSim was in its beta cycle.  We worked together to see if at this beta stage isee NetSim was up to snuff for creating the type of online game that he envisioned. During the process, Steve gave me a lot of valuable feedback on isee NetSim (and rooted out quite a few bugs too).

isee NetSim turned out to be a good fit.  Steve has been using iThink for a long time so he knows it well.  isee NetSim enabled Steve to do all of the interface design inside iThink itself and let isee NetSim take care of converting it to run over the web.  Since the games could now be run in the browser, players would not need to download and install software to play the game.

Steve told me that the game is intended for policy makers, community leaders, educators, artists, business leaders — anyone who should be thinking about the role of arts and culture within a community.  I asked him how he thought Medici’s Lever would be used.

From my perspective, a game like this provides an excellent vehicle for focused discussion about arts & culture policy.  Medici’s Lever surfaces a host of questions about what is necessary to build a rich, sustainable cultural landscape.  It provides a rich context for informed discussion. Models like this are not “true” in an objective sense, but they have great potential utility.”

Freestyle allows the user to "dial up" conditions for real metropolitan regions anywhere in the world.

Freestyle allows the user to "dial up" conditions for real metropolitan regions anywhere in the world.

This is an interesting point about models in general.  This game is fictitious, but the dynamics are useful.  By allowing players to dial in different initial parameters (population size, immigration, birth and death rates, social cohesiveness and several cultural factors), users can create conditions for real metropolitan regions anywhere in the world.

Another important point is that the model runs over the web.  This makes it easy for people who are thinking about these issues to interact with the games and lab and have an informed discussion.  Players do not need a background in modeling and system dynamics. And they don’t need to download and install software.

If you want to experience Medici’s Lever for yourself, click here to play the game now.

Online Learning Labs Explore Systems Problems

February 12th, 2009 2 comments

If you’ve been connecting with folks at isee systems over the years, chances are you’ve read or learned something from Chris Soderquist. Chris is President of Pontifex Consulting and one of isee’s trusted consulting and training partners.

Chris SoderquistBefore branching out on his own, Chris worked for isee as a lead consultant, trainer, and learning environment developer. He co-developed the interactive teaching tool Systems Thinking: Taking the Next Step and has used our software to generate insight and understanding in others for many years. He is a real Systems Thinker and an excellent teacher. We think he is so good at teaching this systems stuff, we rely on him to facilitate our online training and to help us out at conferences and workshops.

Chris likes to tackle timely issues with Systems Thinking and is interested in how sharing models and videos online can help frame the discussion around them. Last year’s spike in fuel prices and public concern about future oil reserves inspired Chris to create a YouTube video and online Learning Labs to explore the supply and demand dynamics of the oil market.

YouTube video: “How long will oil last?”

Online Learning Labs

The following learning labs were developed with iThink and then published to the web using isee NetSim

How much oil is left?

Oil market dynamics

What do you think?

Chris is leading the effort to define an online Learning Lab format. We’d love to hear your reactions. Are there other topics you think this approach would be good for?